Method of twisting wire



July 3, 1934.

c. K. HILL METHOD OF TWISTING WIRE Filed June 5, 1931 2 Sheets-Sheet l [N VEN TOR.

ATTORN Y5 July 3, 1934. c. K. HILL METHOD OF TWISTING WIRE Filed June 5, 1951 2 Sheets-Sheet 2 INVENTOR.

M 9 ATTORNEYS.

Patented July 3, 1934 METHOD @lF TWIS'MNG WERE (Charles K. Hill, Cleveland, @hio Application June 5, 1931, Serial No. 542,842

6 (Claims.

This invention relates'to a method for making nails of the type known as drive screws, and to a method of twisting wire therefor. More particularly, the invention relates to a method of con 5 tinuously twisting a length of wire and then continuously forming nails from this twisted wlre.

Drive screws or nails having a threaded shank are very desirable for many classes of work due to the great holding power possessed by this type of nail. However, the cost of their production has been great because heretofore such nails have been made for the most part by forming the nail with a straight shank from an untwisted piece of wire and thenimparting a thread to each individual nail by means of dies. This operation is costly and also, where hard and tough metals are used for the nails, as is desirable if full advantage is to be taken of the holding power of the drive screw, the dies quickly become worn out on the hard and tough metal. These considerations have made this type of nail so costly as greatly to limit its use and a method which would reduce this cost would result in wider use of such nails.

The cost of production of this type of nail would be greatly reduced if the threaded shank were made before the nail was cut and formed by twisting the uncut wire stock, and the present invention is intended to provide a method of thus twisting wire preparatory to making drive screws.

By the method herein to be described, a complete roll of wire may be twisted and collected into a roll of twisted wire. Ordinarily, a wire having initially a cross section other than circular will be used in order to develop a useful thread on the twisted wire.

It is accordingly an object of the invention to provide a method of twisting wire continuously 49 and uniformly in any desired length. Another object of the invention isto provide a method of forming nails fromtwisted wire. Still another object of the invention is to provide a nail having a threaded shank and prepared from hard and tough metal. A further object of the invention is to provide a method of producing nails having threaded shanks in a continuous and economical manner. To the accomplishment of the foregoing and relatedends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means 5 constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a vertical elevation with parts in section of a wire twisting apparatus adapted to carry out the new method; Fig. 2 is a vertical elevation of a nail-making machine particularly adapted for making nails from twisted wire; Fig.

3 is a perspective view of a piece of wire having a rectangular cross-section and suitable to be twisted by the present method; Fig. Al is a view in perspective of a piece of wire after it has been twisted; Fig. 5 is a view of a piece of wire prepared for the nail-forming operations; and Fig. 6 is a view of a finished nail made according m to the present method.

The new method will be described with relation to theapparatus shown in the drawings, but it will be understood that the method may be carried out by means of apparatus other than Z5 that disclosed and itis not intended to limit the method by reference to any particular apparatus.

Referring to Fig. 1, a wire 7 having a crosssection other than round is passed through a stick 8% or wire-holding means 8 and around a grooved wheel 9, the wire being constrained by this grooved wheel to change its direction The wire then passes over a grooved pulley wheel 11 and from thence to a drum 12 onto which it is wound. The 85 pulley 11 is mounted on a spider 13 and the whole may be balanced by a corresponding spider arm 14 and pulley l5 oppositely disposed. The pulley 9 and the spider 13 carrying the pulley wheel 11 are mounted on a hollow spindle 16 and 99 rotate as a unit. The spindle 16 may be driven through sprockets l7 and 18 by means of a chain 19. l

The drum '12 on which the twisted wire is wound, is mounted on the same center as the spider 13, but rotates independently thereof by means of the sprockets 21 and 22 connected by the chain 23. A change in the speed of rotation oi. the drum may be secured by driving the drum through sprockets 24 and 25 having a dif- 31W ferent gear ratio and it will be obvious that additional sprockets providing other gear ratios may be used. The drum 12 is rotated at a slightly greater speed than the spider 13, the differential drawing the wire through the stick or wire-holding means8 and over the pulleys 9 and 11 as the wire is wound up. The stick 8 has 'rollers 26 and 27 which leave a rectangular open ing or other opening corresponding to the crosssection of the untwisted wire, so that the wire W may pass through this opening, but being held against twisting before this point is reached.

The drum 12 is provided with a removable cover plate or disk 28 which can be drawn back by means of a rack 29 and pinion 31 operated by a hand-wheel 32 to permit removal of a roll of twisted wire.

In operation, a wire of any desired cross-section other than round and composed of any metal suitable. for forming nails having any desired degree of hardness and toughness, is fed through the stick 8 and over the pulleys 9 and 11 to be wound on the drum 12. The drum 12 is revolved at a slightly greater speed than the spider 13 but about the same center; and the differential speed draws the wire through the apparatus and winds it on the drum. The wire will acquire no twist up to the point where it reaches the rollers 26 and 27, but from this point until the wire passes over the pulley wheel 9, a twist will be imparted to the wire corresponding to the number of revolutions by which the speed of the drum 12 exceeds the speed of the spider 13. The wire cannot untwist as it is formed since the rollers 27 hold it firmly against any such tendency. A roll of wire of any desired length may be passed through the wiretwisting machine continuously and again rolled up in uniformly twisted condition on the drum 12. This roll can then be pushed off the drum, which is made slightly tapering for this purpose, by removing the cover plate 28.

It should be noted that the twisted wire always contacts first with the forward portion of the drum 12, or, what is the same thing, with the widest portion of the drum. This is possible because the preceding coils of wire continually slip away from the forward end of the drum and onto the narrower portions, since the drum is tapered for this purpose. Consequently, instead of winding the wire in layers one over the other, with a constantly increasing winding diameter which would increase the speed with which the wire is drawn through the apparatus, the wire is always wound on a surface of the same diameter and is pulled through the apparatus at the same linear speed. In this way it is not necessary to change the speed of rotation of the drum to compensate for an increasing diameter of bundle, but the drum can be rotated at a constant radial speed while pulling the wire through the machine at a constant linear speed.

The roll of twisted wire produced by the previous step is now passed through the nail-making machine shown in Fig. 2. It will be realized that a twisted wire cannot be cut, headed and pointed in the conventional manner, but that the wire must be specially prepared for these operations. In the present method the wire is passed between wire straighteners 33 and 34. The wire is next engaged by a sliding plate 35 which is caused to reciprocate by the bell-crank 36 through the link 37. This sliding plate has a passage 38 therein for the reception of the wire and a strip of metal 39 under which the wire passes. Rollers 41 contact this strip of metal and are resiliently mounted in orifices 42. These orifices slope downwardly so as to narrow the orifice in the direction from which the wire is being fed. The result of this construction is that, as the plate 35 is drawn backwardly by the bell-crank 36 and the link 37, the rollers 41 v are forced rearwardly into the wider part of the orifices where they do not bear on the wire and the plate travels back freely. On the other hand,

when the reciprocating plate begins its forward stroke, friction draws the rollers down into the narrow part of the orifices and causes them to exert pressure on the wire. The effect is that the wire is firmly gripped by the plate 35 and is drawn forward the length of one stroke.

As the wire comes to rest after being drawn forward the determined amount, it is stamped by jaws 43 which have each a half round depression intheir faces which obliterate the twist in the wire and impart a rounded contour at the point affected.

Intermittent motion is imparted to the lower one of these two jaws through a link 44 which connects the jaw holder 45 to a lever 46. This lever has a roller 4'7 which may contact with the shaft 48 through a cam or other means which will impart a rocking motion to the lever 46. A spring 49 retracts the jaw after the latter has stamped the wire.

It is necessary in order that nail-forming means may act upon the wire at the rounded portions 51, that these rounded portions be very accurately placed. In order to effect this accurate spacing, the jaws 43 and the sliding plate 35 are operated from the same source in a synchronized manner. The shaft 48 which imparts a rocking motion to the lever 46 also carries the wheel 52 to which is connected a shaft 53 by means of a key 54 which fits in a key-way 55 in the wheel 52. The shaft 53 connects with the bell-crank 36 and thus imparts a reciprocating motion to the plate 35. Adjustment of the stroke of the plate 35 may be had by moving the key 54 along the key-way 55. It will thus be seen that the shaft 48 not only operates the jaws 43, but also the plate 35. and the jaws will stamp the wire at the end of each forward stroke of the plate. The wheel 52 and appurtenant parts are supported on the frame of the nail machine by means of a hanger 56.

The twisted wire 5'7 which is shown in Fig. 4 now has accurately spaced rounded portions 51 thereon as seen in Figs. 1 and 5. In this form it passes from the jaws 43 until it reaches the grip jaws 59 where the wire is cut off at these rounded portions by knives 61 which are beveled to point the nail. At the same time, a hammer 62 heads the nail, the result being a nail with a threaded shank such as that denominated 63 in Fig. 6.

The new method of making drive screws comprises imparting a uniform twist to long wires, wires up to 1800 feet in length having been successfully twisted, although greater or lesser lengths may also be treated. The product of this step in the process may be a roll of twisted wire, such a product not having been heretofore available due to the difliculty of twisting a wire of this length. A wire having any cross-section other than round may be so treated, square, oblong, and oval wires being suitable and a wire having a rectangular section with concave sides being found particularly valuable due to the depth of thread secured when such a wire is twisted by the present method. The twisted wire is then taken to the nail-forming machine.

Wires of extremely tough and hard metals such as those made from steels containing manganese and carbon may be twisted and the nail 1 produced from this twisted wire is particularly valuable, having great holding power and strength to resist rupture. Drive screws prepared from these metals have been heretofore too expensive to manufacture since the dies used to impart the thread would wear out rapidly. The present method does away with the use of dies, thus lowering the cost of manufacture. Manganese steel drive screws prepared by the present method are very strong and are capable of being driven through very hard materials such as thin steel, vulcanized fiber, etc., without bending.

The step of forming nails from twisted wire is also new, providing a method of handling a twisted wire so that nail-forming operations may be performed thereon accurately and continuously.

e there has been described above apparatus for carrying out the new method, such apiii? bill

"ill

paratus being set forth in my c'opending applications, Serial No. 513,262, filed February 4, 1931, and Serial No. 526,584, filed March 31, 1931, I do not desire to be limited to the use of such apparatus, the method being capable of being performed by apparatus other than that disclosed.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the product and method herein disclosed, provided the step or steps stated by any of the following claims or the equivalent oi such stated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. The method which comprises continuously twisting a wire while positively drawing it forward at a constant linear speed.

2. The method which comprises applying a torque to a traveling wire to permanently twist the same while positively drawing it forward at a constant linear speed.

3. A method of twisting wire which comprises continuously applying atorque to a traveling wire to permanently twist the same and progressively and positively winding the twisted wire into a roll at a constant linear speed.

4. A method of preparing stock for drive screws which comprises continuously unwinding wire from a roll, holding the traveling wire against rotation at a point adjacent said roll, rotating said wire at a point beyond said holding point to permanently twist the same, and positively winding the twisted wire into another roll at a constant linear speed.

5. A method of twisting wire which comprises continuously applying a torque to a traveling wire to permanently twist the same and progressively and positively winding the wire into coils of constant diameter.

6. A method of twisting wire which comprises continuously applying a torque to a traveling wire to permanently twist the same and progressively and positively winding the twisted wire into a roll at a constant rate of linear speed.

CHARLES K. HILL. 

